(1) Field of the Invention
The present invention relates to the identification of objects and the like which may be converted into two dimensional binary representations for purposes of such identification and particularly to the machine identification of data such as hand printed characters. More specifically, this invention is directed to optical recognition apparatus and especially to character recognition apparatus which may read hand printed alphanumeric characters at high speed and with a high degree of accuracy. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus for such character recognition.
(2) Description of the Prior Art
Optical character recognition systems are known in the prior art. Examples of such prior art systems may be seen from U.S. Pat. Nos. 3,159,815, 3,196,398, 3,303,465, 3,417,372, 3,541,511, 3,609,685, 3,629,828, 3,723,970, 3,737,855, 3,766,520, and 4,097,847. Character recognition systems have evolved from those which could identify only machine printed letters and numerals to systems which have the capability of identifying, with an acceptably high degree of accuracy, hand written characters appearing within pre-selected fields. However, for reasons which will be briefly discussed below, those prior systems which had the capability of recognizing alphanumeric hand printed characters have not previously achieved commercial success.
A practical commercial system for the recognition of hand printed characters must meet two somewhat contradictory requirements. Thus, the rejection and substitution rates must be very low for data of the quality typically encountered in the optical character reading environment. However, in order to justify the comparative high cost of such equipment, a hand printed character reading system must have a high data throughput rate. In the prior art, the performance of equipment designed to recognize hand printed characters degraded rapidly as the quality of the data became poorer. While there have previously been comparatively uncomplicated systems which had the capability of reading excellent quality data at high speed, such systems were characterized by a rapid increase in the rejection and substitution rates as the data quality decreased. Those complex character reading systems that have had the ability to analyze poor quality data, particularly to analyze the subtle shape distinctions in certain conflict pairs, have been characterized by a data throughput rate which was too slow for commercial application.